Antifriction bearing for use in apparatus for damping fluctuations of torque in power trains of motor vehicles

ABSTRACT

A bearing which can be used between two coaxial flywheels has an inner race, an outer race, one or more annuli of antifriction bearing elements between the two races, a metallic or plastic enclosure which surrounds the peripheral surface of the outer race and a portion of the internal surface of the inner race and has a wall extending along first axial ends of the races. The wall has an outwardly bulging pocket for confinement of lubricant in addition to that which is confined in the space between the inner and outer races. Such space is sealed at the second axial ends of the races by a ring which is installed between the two races or surrounds a portion of the peripheral surface of the outer race and sealingly engages the inner race.

BACKGROUND OF THE INVENTION

The invention relates to improvements in apparatus for dampingfluctuations of torque in power trains, particularly in the power trainsof motor vehicles. More particularly, the invention relates toimprovements in bearings between rotary components (such as coaxialflywheels) which can be utilized in the above outlined apparatus. Stillmore particularly, the invention relates to improvements in frictionreducing units which can be utilized between the flywheels of clutchplates, torque damping apparatus and like assemblies.

Apparatus in which the improved bearings can be put to use aredisclosed, for example, in commonly owned U.S. patent application Ser.No. 07/708,934 filed May 31, 1991 by Wolfgang Reik et al. for "Apparatusfor transmitting torque in the power trains of motor vehicles"; incommonly owned German patent application Serial No. P 40 27 6295; incommonly owned copending U.S. patent application Ser. No. 07/708,930filed May 31, 1991 by Oswald Friedmann for "Apparatus for transmittingtorque to between the engine and the transmission of a motor vehicle";and in commonly owned copending U.S. patent application Ser. No.07/708,935 filed May 31, 1991 by Oswald Friedmann for "Twin-flywheelapparatus for transmitting torque in the power train of a motorvehicle".

OBJECTS OF THE INVENTION

An object of the invention is to provide a bearing whose useful life islonger than that of heretofore known bearings.

Another object of the invention is to provide an antifriction bearingwhich need not be lubricated subsequent to installation between two ormore rotary parts or between one or more stationary parts and one ormore rotary parts.

A further object of the invention is to provide a compact bearing whichcan stand pronounced axial and/or radial stresses when installed betweentwo flywheels or elsewhere between two rotary components or a rotarycomponent and a stationary component.

An additional object of the invention is to provide a simple, compactand inexpensive bearing whose cost is a fraction of the cost of aconventional bearing but which can stand all kinds of stresses that canbe withstood by heretofore known bearings.

Still another object of the invention is to provide an apparatus whichembodies one or more bearings of the above outlined character.

A further object of the invention is to provide a bearing which can beinstalled in close or immediate proximity to one or more heat generatingparts or devices without affecting its useful life and/or quality ofoperation.

Another object of the invention is to provide novel and improved meansfor preventing the escape of lubricant for the rolling elements of theabove outlined bearing.

An additional object of the invention is to provide a bearing which canbe installed in or removed from an apparatus or the like with littleloss in time.

Still another object of the invention is to provide a prefabricated unitor module which embodies the above outlined antifriction bearing.

A further object of the invention is to provide a novel combination ofan antifriction bearing and an enclosure for its races.

Another object of the invention is to provide a novel and improvedmodule which embodies the above outlined antifriction bearing.

An additional object of the invention is to provide a torquetransmitting apparatus, particularly for use in motor vehicles, whichembodies a bearing of the above outlined character.

Still another object of the invention is to provide a novel and improvedmodule which reduces friction between the flywheels of a compositeflywheel in the above outlined torque transmitting apparatus.

A further object of the invention is to provide a novel and improvedmethod of confining a large quantity of lubricant for the rollingelements between the races of an antifriction bearing.

SUMMARY OF THE INVENTION

One feature of the invention resides in the provision of an antifrictionbearing for use between coaxial first and second rotary components,e.g., between the primary and secondary flywheels of a compositeflywheel in an apparatus for damping torque in the power train betweenthe engine and the variable-speed transmission of a motor vehicle. Theimproved bearing comprises an outer race, an inner race which is coaxialwith, at least partially surrounded by and disposed radially inwardly ofthe outer race, and an enclosure or jacket including a first wallbetween the outer race and one of the rotary components, and a secondwall extending from the first wall inwardly along an axial end of theouter race to an axial end of the inner race. The second wall has atleast one lubricant-confining pocket which extends substantially axiallyof the races and away from their aforementioned axial ends. The onecomponent (which is adjacent the first wall of the enclosure) canconstitute the secondary flywheel of the aforementioned compositeflywheel.

The enclosure can contain a heat insulating material, and the secondwall can include a radially inner portion which is surrounded by theinner race of the bearing. The internal surface of the inner race can beprovided with a recess for the radially inner portion of the secondwall. Such radially inner portion of the second wall and the inner racecan define at least one sealing gland with one or more clearances.Alternatively or in addition to the at least one sealing gland, theradially inner portion of the second wall and the inner race can defineat least one friction bearing. The radially inner portion of the secondwall and the inner race have confronting surfaces and at least one ofthese surfaces can be provided with at least one annular projectionextending toward the other surface.

The enclosure can contain or consist of a plastic material, and suchplastic material is preferably a heat insulating material.Alternatively, the enclosure can be made of, or can contain, a metallicsheet material.

The bearing can further comprise a preferably reinforced sealing ringwhich operates between the inner and outer races, and such sealing ringis preferably disposed at those axial ends of the races which are remotefrom the second wall of the enclosure. The outer wall can be providedwith an axial extension which is adjacent its internal surface at thatend of the outer race which is remote from the second wall of theenclosure, and a portion of the sealing ring can surround such extensionof the outer race. The external surface of the outer race can beprovided with an annular recess which is remote from the second wall ofthe enclosure, and the substantially axially extending radially outerportion of the sealing ring preferably extends into such recess. Theradially outer portion of the sealing ring can be confined between theouter race and the first wall of the enclosure and can comprise anelastic annular bead which is preferably stressed in the axial and/orradial direction of the races. At least one of the confronting surfacesof the outer race and the first wall of the enclosure (such surfacesflank the bead) can be provided with an annular groove which receivesthe bead in stressed condition.

In accordance with one presently preferred embodiment, the inner race ofthe bearing has a substantially L-shaped cross-sectional outline andincludes a substantially axially extending first leg and a second legwhich can extend substantially radially of the races and inwardly fromthe first leg. The second leg of the inner race and one of the rotarycomponents have means for coupling the second leg to such rotarycomponent, preferably the primary flywheel. The bearing furthercomprises at least one row of rolling elements between the inner andouter races, and the axially extending first leg of the inner race canbe provided with a track for the at least one row of rolling elements.At least one leg of the just discussed second race can be made of ametallic sheet material.

The rolling elements of the at least one row can constitute spheres, andsuch rolling elements can be confined exclusively by the inner and outerraces, i.e., the bearing need not employ a cage for the rollingelements.

At least one of the races, particularly the outer race, can be split tofacilitate introduction of rolling elements between the inner and outerraces. In other words, the outer race is preferably expandible andcontractible, and such bearing preferably further comprises means (suchas the aforementioned sealing ring) for maintaining the outer race incontracted condition upon completed introduction of rolling elementsbetween the inner and outer races.

The enclosure and at least one of the races (such as the outer race) canconstitute a prefabricated module to facilitate and simplify theassembly of the bearing with the rotary components.

The second wall of the enclosure includes a first portion between thefirst wall and the at least one pocket and a second portion, with the atleast one pocket located radially between the first and second portionsof the second wall. At least one of the two portions of the second wallcan make an oblique angle with the common axis of the inner and outerraces. Such at least one portion of the second wall can constitute ahollow conical frustum.

Another feature of the invention resides in the provision of a bearingwhich comprises an outer race having first and second axial ends and aperipheral surface, an inner race which is coaxial with and is at leastpartially surrounded by the outer race and has first and second axialends at the respective axial ends of the outer race, and an enclosurehaving a first wall adjacent the peripheral surface of the outer race, asecond wall at the first axial ends of the two races, and a third wallsurrounded by a portion at least of the internal surface of the innerrace.

A further feature of the invention resides in the provision of a bearingincluding an outer race having a peripheral surface and first and secondaxial ends, an inner race which is coaxial with and is at leastpartially surrounded by the outer race and has first and second axialends at the respective axial ends of the outer race, and an enclosureincluding a first wall adjacent the peripheral surface of the outer raceand a second wall at the first axial ends of the two races. Theenclosure consists of a plastic material, particularly a heat insulatingplastic material.

An additional feature of the invention resides in the provision of abearing comprising an outer race having an internal surface, first andsecond axial ends and an annular extension adjacent the internal surfaceat the first axial end, an inner race coaxial with and at leastpartially surrounded by the outer race and having first and second axialends at the respective axial ends of the outer race, and a reinforcedsealing ring which sealingly surrounds the extension of the outer raceand sealingly engages the first axial end of the inner race.

Still another feature of the invention resides in the provision of abearing which can be used between first and second rotary components andcomprises an outer race, an inner race coaxial with and at leastpartially surrounded by the outer race and having a substantiallyL-shaped cross-sectional outline with first leg extending substantiallyaxially of the races and a second leg, means for coupling the second legwith one of the rotary components, and at least one row of rollingelements between the two races. The first leg of the inner race has atrack for the rolling elements.

A further feature of the invention resides in the provision of a bearingcomprising an outer race, an inner race coaxial with and at leastpartially surrounded by the outer race, and at least one row ofspherical rolling elements which are confined between the two races. Therolling elements are confined exclusively by the two races, i.e., thebearing need not be provided with a cage for the rolling elements.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved bearing itself, however, both as to its construction and themode of installing the same, together with additional features andadvantages thereof, will be best understood upon perusal of thefollowing detailed description of certain presently preferred specificembodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an axial sectional view of an apparatus for damping torquebetween the engine and the variable-speed transmission of a motorvehicle wherein an improved ant-friction bearing is installed betweentwo coaxial flywheels one of which is driven by the engine and the otherof which transmits torque to the transmission by way of a frictionclutch;

FIG. 2 is an enlarged view of a detail II in the structure of FIG. 1;

FIG. 3 is a view similar to that of FIG. 2 but showing a modifiedantifriction bearing; and

FIG. 4 is a fragmentary axial sectional view of an apparatus wherein theflywheels surround a third antifriction bearing.

DESCRIPTION OF PREFERRED EMBODIMENTS

The apparatus which is shown in FIG. 1 comprises a composite flywheel 1including a first or primary flywheel 2 which can be coupled to theoutput element (e.g., a crankshaft) of an internal combustion engine ina motor vehicle, and a second or secondary flywheel 3 which is coaxialwith the primary flywheel 2 and can transmit torque to the clutch plate5 of a friction clutch 4. The clutch plate 5a carries or includes a hub5a which transmits torque to the input shaft of a variable-speedtransmission in the motor vehicle. The internal surface of the hub 5ahas axially parallel teeth which cooperate with complementary externalteeth of the input shaft.

The apparatus of FIG. 1 further comprises a friction reducing unit 6which is installed between the flywheels 2, 3 and includes orconstitutes an antifriction ball bearing 6a having an inner race 16, anouter race 17 spacedly surrounding at least a portion of the inner race16, and a row or annulus of spherical rolling elements 6a' (see alsoFIG. 2). The bearing 6a is disposed radially inwardly of an annulus ofbolts or other suitable fasteners 8 which serve to separably affix theflywheel 2 to the output element of the engine and have externallythreaded shanks extending through circular openings (holes or bores) ina radially extending flange-like portion 14 of the flywheel 2.

A damper 9 is disposed between and serves to oppose angular movements ofthe flywheels 2, 3 relative to each other. The illustrated damper 9comprises arcuate elongated energy storing elements 10 in the form ofcoil springs which extend circumferentially of the composite flywheel 1and are confined in the annular radially outermost portion orcompartment 12 of an annular chamber 11 which is defined by the primaryflywheel 2. At least a portion of the chamber 11 is filled with aviscous hydraulic lubricant, such as oil or grease.

The primary flywheel 2 comprises a first part or section 13 and a secondpart or section 19. The section 13 includes the aforementioned radiallyextending portion 14 which is adjacent the engine and is traversed bythe shanks of the fasteners 8, a centrally located ring-shaped portionor protuberance 15 which is integral with the radially innermost part ofthe portion 14 and has a smaller-diameter cylindrical end portion 15asurrounded by the inner race 16 of the antifriction bearing 6a, and anaxially extending dished or substantially C-shaped (in cross-section)radially outermost portion 18 which is integral with the radiallyoutermost part of the portion 14 and surrounds the compartment 12 of theannular chamber 11. The section 13 constitutes the main part of theflywheel 2 and the free end of its axially extending portion 18 iswelded to the radially outermost portion of the second section 19. Eachof the sections 13, 19 can be made of metallic sheet material. The holesor bores (openings) of the flange-like radial portion 14 forming part ofthe main section 13 of the primary flywheel 2 surround the protuberance15.

The bearing 6a can comprise two or more rows of spherical, barrel-shapedor other suitable rolling elements 6a'. However, it is presentlypreferred to employ a single row or annulus of spherical rollingelements which may but need not be confined in a cage, i.e., suchrolling elements may be confined exclusively by the races 16, 17 of thebearing 6a. A cage 6b is shown in FIG. 2.

The illustrated secondary flywheel 3 constitutes or resembles a disc andspacedly surrounds the outer race 17 of the bearing 6a. To this end, theflywheel 3 is provided with a centrally located circular opening 3ahaving a diameter which slightly exceeds the diameter of the peripheralsurface of the outer race 17.

The radially outermost portion 18 of the main section 13 of the flywheel2 surrounds at least the radially outermost portions of the energystoring elements 10 of the damper 9 and can be provided with a friction-and wear-reducing internal liner 18a which comes in direct contact withthe elements 10. These elements 10 bear against the liner 18a at leastwhen the flywheel 2 rotates so that the elements 10 are subjected to theaction of centrifugal force. The radially outermost part of the radiallyextending portion 14 of the section 13 cooperates with the section 19 toflank the compartment 12 of the chamber 11 and hence the energy storingelements 10 of the damper 9.

The energy storing elements 10 of the damper 9 are installed in discretearcuate recesses which form part of the compartment 12 and are separatedfrom each other by abutments or stops (one shown in the lower part ofFIG. 1, as at 12a) which alternate with the elements 10 (as seen in thecircumferential direction of the flywheel 2) and can form integral(inwardly deformed) parts of the radially extending portion 14 andsection 19. Each of these abutments or stops 12a can be said toconstitute a pocket which is depressed into the external surface of therespective part (portion 14 or section 19) of the flywheel 2.

The secondary flywheel 3 carries abutments or stops 21 for the energystoring elements 10 of the damper 9. The stops 21 are lugs or arms whichare welded to and extend radially outwardly from a cylindrical portion23 of the housing or cover 22 of the friction clutch 4. The cylindricalportion 23 of the clutch housing 22 is non-rotatably secured to theperiphery of the secondary flywheel 3 by a set of radially disposed pins23a. When the flywheels 2, 3 assume their neutral positions in which theenergy storing elements 10 are unstressed or are subjected to a minimalstress, the stops 21 are disposed in the gaps between the neighboringpairs of axially aligned stops 12a on the flywheel 2. One stop of eachpair of stops 12a is provided on the section 19, and the other stop ofeach pair of stops 12a is provided on the radially extending flange-likeportion 14 of the main section 13.

The secondary flywheel 3 serves to transmit torque to as well as tocenter the axially extending cylindrical or substantially cylindricalportion 23 of the clutch housing 22. The latter further comprises aradially inwardly extending portion 24 which is remote from the stops 21and carries a diaphragm spring 25 forming part of the clutch 4. Thediaphragm spring 25 is tiltable relative to the portion 24 of thehousing 22 and acts not unlike a two-armed lever. The radially outerportion of the diaphragm spring 25 urges an axially movable pressureplate 26 of the clutch 4 against the adjacent friction lining of theclutch plate 5 when the clutch 4 is engaged. This causes the otherfriction lining of the clutch plate 5 to frictionally engage an annularfriction surface 29 of the secondary flywheel 3 so that the flywheel 3can drive the hub 5a (and hence the input shaft of the variable-speedtransmission) through the medium of the clutch plate 5.

FIG. 1 shows that at least the major part of the annular chamber 11 (andthe entire compartment 12) is located radially outwardly of thesecondary flywheel 3. This contributes to compactness of the apparatusbecause the disc-shaped flywheel 3 can be installed in immediate orclose proximity to the radially extending portion 14 of the main section13 of the primary flywheel 2, i.e., close to the engine of the motorvehicle in which the improved apparatus is put to use. The flywheel 3and the portion 14 of main section 13 of the flywheel 2 define arelatively narrow radially extending clearance 27. All in all, the justdescribed dimensioning and mounting of the flywheel 3 (so that it can besurrounded by the annular chamber 11 of the flywheel 2) contributesignificantly to compactness of the apparatus as considered in the axialdirection of the flywheels 2, 3 and clutch 4 including its clutch plate5. In order to ensure that the flywheel 3 can be placed as close to theengine (i.e., to the portion 14 of the flywheel 2) as possible, one(28)of the sealing devices 28, 34 for the chamber 11 is installedbetween the peripheral surface of the axially extending portion 23 ofthe clutch housing 22 and the internal surface of the radially innermostportion of the section 19. As can be seen in FIG. 1, the improvedapparatus is designed in such a way that the radial clearance 27 betweenthe portion 14 and the flywheel 3 does not or need not accommodate anyparts which would necessitate a widening of such clearance in the axialdirection of the flywheels 2 and 3.

The radially extending clearance 27 can be used to establish a portionof a path for the flow of a coolant (such as air) between the flywheels2 and 3 and to thus reduce the likelihood of overheating of the radialportion 14 by the flywheel 3 whose temperature is raised by frictionheat when its surface 29 slips relative to the adjacent lining of theclutch plate 5. Another portion of the aforementioned path isestablished by passages 30 which are provided in the secondary flywheel3 radially inwardly of the annular friction surface 29 and communicatewith the adjacent portions of the clearance 27. Cool atmospheric air isdrawn into the passages 30 when the flywheel 3 rotates, and streams orjets of such air impinge upon the adjacent zones of the radiallyextending portion 14. The passages 30 can be provided in addition to orin lieu of one or more substantially axially parallel passages 31 in theradially extending portion 14 of the main section 13. The passages 31admit cool air from that side of the radially extending portion 14 whichconfronts the engine. The cooling action of air which enters theclearance 27 can be enhanced still further by the provision of passages(e.g., in the form of cutouts or recesses) 32 in the peripheral surfaceof the flywheel 3 inwardly adjacent the axially extending portion 23 ofthe clutch housing 22. The passages 32 can discharge heated air into theinterior of the clutch housing 22 radially outwardly of the frictionsurface 29 of the secondary flywheel 3. The illustrated passages 32 arenotches or recesses in the peripheral surface of the flywheel 3 and aresurrounded by the adjacent portions of the internal surface of theaxially extending portion 23 of the clutch housing 22. Each of thepassages 30, 31, 32 (or at least some of these passages) can be round orcan be elongated in the circumferential direction of the compositeflywheel 1.

The secondary flywheel 3 is further provided with passages 33 (e.g., inthe form of holes or bores) which register with the openings 7 in theradially extending portion 14 of the main section 13 of the flywheel 2and serve for introduction of shanks and heads of the fasteners 8. Thehead of the lower fastener 8 which is shown in FIG. 1 is in the processof advancing toward the radial portion 14 and is located in thecorresponding hole or bore 33 of the flywheel 3. Insertion of thefasteners 8 into the apparatus (to assume positions corresponding tothat of the upper fastener 8 in FIG. 1) is further facilitated by theprovision of holes or bores 36 in the radially extending portion of theclutch plate 5 and by the provision of holes or bores 37 in the radiallyinwardly extending elastic prongs 25a of the diaphragm spring 25. Eachhole or bore 36 registers with a hole or bore 33 and with a hole or bore37. This renders it possible to employ a relatively simple tool (notshown) whose working end can enter the hexagonal or otherwiseconfigurated non-circular recess or socket in the exposed end face ofthe head of a fastener 8 in order to facilitate introduction of suchfastener through the aligned holes or bores 37, 36, 33 (in such order)and rotation of the inserted fastener until the shank properly engagesthe internal thread in the tapped hole of the output element of theengine and the head comes into abutment with the right-hand (inner) sideof the radial portion 14 of main section 13 of the primary flywheel 2.

As already mentioned hereinbefore, the sealing device 28 for the chamber11 operates between the external surface of the axially extendingportion 23 of the clutch housing 22 and the adjacent side of theradially inner portion of the section 19. This sealing device is locatedradially outwardly of the sealing device 34 which operates between theinner side of the radially extending portion 14 and the adjacent side ofthe radially outermost portion of the flywheel 3. At least the sealingdevice 34 can comprise a membrane or a diaphragm spring which reactsagainst the radially extending portion 14 and bears against the flywheel3. Alternatively, the radially outermost portion of the sealing device34 can sealingly engage the internal surface of the axially extendingportion 23 of the clutch housing 22, and the radially innermost portionof such sealing device then bears against the adjacent inner side of theradially extending portion 14 to seal the radially outermost part of theclearance 27 from the adjacent portion of the chamber 11. Such mountingof the sealing device 34 is preferred at this time because the axiallyextending portion 23 can serve as a means for centering this sealingdevice.

FIG. 1 further shows a ring-shaped starter gear 35 which is welded tothe section 19 of the primary flywheel 2.

The composite flywheel 1 and the friction clutch 4 (including its clutchplate 5) are preferably assembled into a module right at themanufacturing plant to simplify installation of such module in the powertrain between the engine and the variable-speed transmission of a motorvehicle. Assembly of the flywheels 2, 3 and clutch 4 into aprefabricated module also simplifies storage and shipment to theautomobile making concerns. The manner in which the prefabricated orpreassembled module can be mounted on the output element of an engine(with fasteners 8 which are caused to pass through aligned holes orbores 37, 36, 33 and the respective openings 7) was describedhereinabove.

The assembly of the module is preferably carried out in the followingway: The first step involves assembly of the clutch housing or cover 22with the secondary flywheel 3 while the clutch plate 5 is locatedbetween the friction surface 29 and the pressure plate 26. The latter isaxially movably but non-rotatably secured to the housing 22 by leafsprings 26a. This results in the assembly of a smaller module orsubmodule including the flywheel 3 and the friction clutch 4. The nextstep involves insertion of the flywheel 3 of such submodule into thespace within the annular chamber 11 and into close proximity to theradially extending portion 14 of main section 13 of the primary flywheel2 to establish the clearance 27, and the third step includes welding ofthe section 19 to the section 13 (subsequent to insertion of energystoring elements 10 into the compartment 12 of the annular chamber 11).The section 19 of the primary flywheel 2 can be slipped onto thecylindrical portion 23 of the clutch housing 22 in a direction from theright, as viewed in FIG. 1. The aforementioned third step is preceded bymounting of the sealing device 34 on the axially extending portion 23 ofthe clutch housing 22 or on the radially extending portion 14 of themain section 13. The same applies for the mounting of the antifrictionbearing 6a

which is installed in the central opening 3a of the flywheel 3 or on thefree end portion 15a of the protuberance 15 of the flywheel 2 before theflywheel 3 is introduced into the space within the annular chamber 11.Thus, the bearing 6a forms part of the aforementioned prefabricatedmodule which is ready to be secured to the output element of the engine.

The fasteners 8 are preferably introduced into the openings 7 of theradially extending portion at the assembly plant. They are held inrequisite positions for rapid and convenient introduction of theirshanks into the tapped bores or holes of the output element of theengine. This can be achieved in a simple way by utilizing elasticinserts which yieldably hold the fasteners 8 in positions correspondingto that of the lower fastener 8 of FIG. 1, i.e., in such axial positionsthat the tips of their shanks do not extend, or do not extendappreciably, beyond the exposed side of radial portion 14 of mainsection 13 of the primary flywheel 2. It is presently preferred toutilize fasteners 8 of the type known as hexagonal socket screws orbolts.

The clutch plate 5 is centered between the friction surface 29 of theflywheel 3 and the pressure plate 26 of the clutch 4 in theprefabricated or preassembled module in such angular position that eachof its holes or bores 36 is in full or adequate alignment with a hole orbore 37 of the diaphragm spring 25 and with a hole or bore 33 of theflywheel 3. The fully assembled module is then ready for storage,shipment or attachment to the output element of the engine. Attachmentto the output element of the engine takes up a small fraction of thetime which would be required in the absence of assembly of the compositeflywheel 1 and friction clutch 4 into a module because the clutch plate5 would have to be centered at the locus of installation into the powertrain of the motor vehicle and such centering, as well as othercentering operations, would necessitate the utilization of aconventional centering mandrel which is not needed for the purpose ofinstalling the module including the composite flywheel 1 and the clutch4 of the improved apparatus. Insertion of fasteners 8 in theaforedescribed manner (to positions corresponding to that of the lowerfastener 8 of FIG. 1) also contributes to simplicity of installation ofthe module and to a reduction of the interval of time which is requiredto carry out such installation.

The heretofore described features of the improved apparatus aredescribed and shown in the aforementioned commonly owned copendingpatent application Ser. No. 07/708,934.

In accordance with a feature of the invention, and as shown in detail inFIG. 2, the circular central opening 3a of the secondary flywheel 3receives the antifriction bearing 6a as well as an enclosure or jacket38 which can be made of heat insulating plastic material and cooperateswith a reinforced sealing ring 53 to seal the space between (such as oilor grease) which is used to contact the rolling elements 6a'. Theenclosure 38 includes a first wall 39 which surrounds the entireperipheral surface of the outer race 17 and is integral with theradially outermost portion 41 of a radially extending second wall 40.The wall 40 is adjacent those axial ends of the races 16, 17 which areremote from the sealing ring 53, and this wall further comprises aradially inner portion 45 as well as a lubricant-confining pocket 40abetween the portions 41, 45. The pocket 40a extends axially of theflywheels 2, 3 in a direction away from those axial ends of the races16, 17 which are engaged by the sealing ring 53. The enclosure 38further comprises a third wall 46 which is integral with the radiallyinner portion 45 of the second wall 40 and is received in a recess orcutout 50 provided in the internal surface of the inner race 16 at thataxial end which is remote from the sealing ring 53. The first wall 39and the radially outer portion 41 of the second wall 40 sealingly engagethe outer race 17, and the radially inner portion 45 of the second wall40 can sealingly engage the inner race 16 so that the right-hand axialend of the space 48 between the races 16, 17 and in the pocket 40a isreliably sealed from the atmosphere. The third wall 46 also contributesto the sealing action between the enclosure 38 and the inner race 16.

The pocket 40a is defined by a radially extending central portion 43 andtwo substantially mirror symmetrical frustoconical portions 42, 44 ofthe second wall 40 of the enclosure 38. The frustoconical portion 42tapers toward the common axis of the flywheels 2, 3 in a direction awayfrom the sealing ring 53, and the frustoconical portion 44 tapers towardthe common axis in the opposite direction, i.e., toward the sealing ring53. It is within the purview of the invention to modify thecross-sectional area of the pocket 40a by replacing the frustoconicalportion 42 and/or 44 with a cylindrical or even polygonal portion.

The free end 47 of the third wall 46 of the enclosure 38 constitutes ashort radially inwardly extending collar which abuts the adjacentradially extending shoulder 49 in the recess 50 of the inner race 16.The lubricant can completely or at least partially fill the internalspace 48 in the pocket 40a and between the races 16, 17. This pocketenlarges the capacity of the bearing 6a to store lubricant for therolling elements 6a', i.e., the rolling elements and their tracks(defined by the internal surface of the outer race 17 and by theexternal or peripheral surface of the inner race 16) can be adequatelylubricated for long periods of time. This prolongs the useful life ofthe entire bearing 6a and of the apparatus including the bearing 6a andthe flywheels 2, 3. The provision of a relatively large space 48 forstorage of a substantial supply of lubricant ensures that the rollingelements 6a' and their tracks are adequately lubricated for long periodsof time even if some of the lubricant is free to escape at the secondand/or third wall 40 or 46 of the enclosure 38 and/or at the sealingring 53.

The radially outer portion 41 of the second wall 40 constitutes aninsert between the right-hand end face of the outer race 17 and theadjacent radially inwardly extending collar 49a of the secondaryflywheel 3. The collar 49a is provided at that axial end of the outerrace 17 which is remote from the sealing ring 53. The portion 41 of thesecond wall 40 determines the axial position of the outer race 17 (andhence of the entire antifriction bearing 6a) relative to the secondaryflywheel 3.

The collar 49a of the flywheel 3 surrounds the pocket 40a, i.e., thelatter need not extend axially beyond the right-hand end face of theflywheel 3. The collar 47 of the third wall 46 of the enclosure 38 isclosely adjacent to but need not necessarily touch the peripheralsurface of the free end portion 15a of the hollow protuberance 15 of themain section 13 of the primary flywheel 2. The recess 50 is an annularclearance between a portion 51 of the inner race 16 and the peripheralsurface of the free end portion 15a of the protuberance 15.

The radially extending portion 45 of the second wall 40 can sealinglycontact the right-hand end face of the portion 51 of the inner race 16or it can form therewith a narrow clearance or gap. In the embodiment ofFIG. 2, the portion 45 is in actual sealing engagement with theright-hand end face of the portion 51. The portions 45, 51 form aso-called contact seal if they are in actual contact with each other, ora diaphragm gland if they define the aforementioned narrow clearance.

A gland is defined by the third wall 46 of the enclosure 38 and theadjacent internal surface of the axially projecting portion 51 of theinner race 16. The internal surface of the portion 51 of the inner race16 has a substantially triangular annular projection 53a which bitesinto the material of the third wall 46 when the mounting of theenclosure 38 on the races 16, 17 is completed. The apex of theprojection 53a can actually penetrate into the material of the wall 46to thus establish a highly reliable sealing action. The number ofprojections 53a can be increased to two or more. Furthermore theprojection or projections 53a can be replaced by, or used jointly with,one or more analogous annular projections at the radially outer side ofthe wall 46, such annular projections being caused to penetrate into theportion 51 of the inner race 16 when the assembly of the races 16, 17with the enclosure 38 is completed. Penetration of the projection orprojections 53a of the portion 51 into the third wall 46 and/orpenetration of one or more projections on the third wall 46 into theinternal surface of the portion 51 of the inner race 16 is particularlysatisfactory if the enclosure 38 is applied with a certain amount oftension in the radial direction so that the second wall 40 is stretchedradially to ensure reliable penetration of projections (including thatshown at 53a) into the material of the wall 46 and/or into the materialof the inner race 16 at the inner side of the portion 51. One or morecontact seals and/or glands can be established between the third wall 46and the portion 51 and/or shoulder 49 of the inner race 16 when theapplication of the enclosure 38 is completed.

It is presently preferred to make the enclosure 38 from a temperatureresistant and thermally insulating plastic material. A suitable materialis polyamide or PEEK (polyether ether ketone).

The sealing ring 53 is disposed at those axial ends of the races 16, 17which are remote from the second wall 40 of the enclosure 38 and servesto seal the respective axial end of the space 48 between the two races.This sealing ring is carried by the outer race 17 and is in multiplesealing engagement with the peripheral surface of the inner race 16. Anaxially extending portion 54 of a metallic reinforcing section 59 of thering 53 surrounds the adjacent portion of the peripheral surface of theouter race 17 and is surrounded, in turn, by the adjacent portion of thefirst wall 39 of the enclosure 38. The axially extending portion 54 ofthe reinforcing section 59 of the ring 53 surrounds an axial extension55 of the outer race 17, the extension 55 being adjacent the internalsurface of the outer race and being surrounded by the axially extendingportion 54. The left-hand end of the peripheral surface of the outerrace 17 is formed with an annular recess 56 which surrounds theextension 55 and receives the axially extending portion 54 of thesection 59. This recess 56 is surrounded by the wall 39 of the enclosure38 and further accommodates a plastic section 60 which is vulcanized orotherwise reliably secured to (e.g., extruded onto) the section 59 andhas an elastic annular bead 62 received in an external groove 63 formingpart of the recess 56. The radially inner portion 61 of the section 60carries two elastic lips 57, 58 which sealingly engage the peripheralsurface of the inner race 16. The plastic section 60 can be said toconstitute a reinforcement for the metallic section 59 of the sealingring 53 and/or vice versa.

For example, the section 60 and its portion 61 (including the sealinglips 57, 58) can be made of an elastically yieldable plastic material,e.g., an elastomer such as Vitron (TRADEMARK).

The portion 54 and its free end 59a are preferably a press fit on theextension 55 of the outer race 17 to ensure that the ring 53 will remainin an optimum position relative to the races 16 and 17. The bead 62 isalso a press fit in the groove 63 to ensure that the ring 53 cannotmigrate in the axial direction of the outer race 17. In addition, thisbead is surrounded by the adjacent portion of the first wall 39 of theenclosure 38. Still further, the bead 62 can be received in the wall 39with a snap action to establish a form-locking connection between theenclosure 38 and the sealing ring 53. To this end, the internal surfaceof the wall 39 is provided with an annular groove 64 which receives theradially outer portion of the properly installed bead 62 and is locatedradially outwardly of and opposite the groove 63 in the peripheralsurface of the extension 55. Thus, the sealing ring 53 can be fixedagainst axial movement along the races 16, 17 in a number of differentways to even further reduce the likelihood of escape of any, or anyappreciable quantities of, lubricant from the space 48 between the races16 and 17 and in the pocket 40a. The arrangement is preferably such thatthe bead 62 of the elastically deformable section 60 is stressed in theaxial and radial directions as a result of engagement by the surfacesbounding the grooves 63 and 64.

The character 59b denotes in FIG. 2 that portion of the metallic section59 of the sealing ring 53 which is vulcanized or otherwise connected tothe portion 61 of the elastically deformable section 60. The material ofthe sealing lips 57, 58 may but need not be the same as that of the bead62.

The sealing ring 53 prevents, or at least greatly reduces, leakage oflubricant from the space 48 at the respective axial ends of the races16, 17, and the enclosure 38 performs the same function at the otheraxial ends of the two races. A reliable sealing action between theenclosure 38 and the ring 53 is established in the region of theelastically deformable bead 62. The sealing ring 53 further cooperateswith the enclosure 38 and with the races 16, 17 to form aself-sustaining prefabricated unit or module which can be installedbetween the flywheels 2, 3 with little loss in time. Moreover, theradially extending portion 41 of the second wall 40 of the enclosure 38cooperates with the collar 49a of the secondary flywheel- 3 to ensurepredictable axial positioning of the races 16, 17 relative to theflywheel 3.

An important advantage of the structure which is shown in FIG. 2 is thatthe useful life of the bearing 6a is much longer than that of heretoforeknown antifriction bearings for use between two flywheels or between astationary component and a rotary component. Thus, the pocket 40aconstitutes a reservoir for storage of an additional substantial amountof lubricant (such as grease) for the rolling elements 6a', namely anamount in addition to that which can be confined between the internalsurface of the outer race 17 and the external or peripheral surface ofthe inner race 16. In the absence of any obstructions outwardly adjacentthe second wall 40 of the enclosure 38, the reservoir or pocket 40a canbe enlarged in a direction toward the hub 5a and the clutch plate 5 ofthe friction clutch 4 which is shown in FIG. 1. The larger the capacityof the pocket 40a, the longer is the useful life of the bearing 6a andof the apparatus in which the bearing is put to use. This is ofparticular importance in apparatus of the type shown in FIG. 1 in whichthe bearing 6a is accessible only upon at least partial dismantlingand/or upon separation of the apparatus from the input element of theengine.

The third wall 46 of the enclosure 38 exhibits the advantage that it canestablish with the inner race 16 at least one contact seal or a gland toeven further reduce the likelihood of escape of any, or the likelihoodof escape of a substantial quantity of, lubricant from the pocket 40a.Such sealing action is enhanced when the bearing 6a rotates and thethird wall 46 is subjected to the action of centrifugal force whichtends to urge it radially outwardly toward the internal surface of theinner race 16. The seal or seals between the third wall 46 and the innerrace 16 assist the seal or seals between the radially inner portion 45of the second wall 40 and the adjacent end face of the inner race 16.The seal or seals between the inner race 16 and the third wall 46 of theenclosure 38 can include one or more annular contact seals and/or one ormore glands each with one or more clearances. As stated above, thesealing action between the third wall 46 and the race 16 improves whenat least the outer race 17 and the enclosure 38 rotate so that the wall46 is acted upon by centrifugal force.

The annular projection or projections 53a also contribute to the sealingaction between the third wall 46 and the inner race 16. Such projectionor projections and the adjacent portion or portions of the neighboringpart (46 or 16) cooperate to form one or more contact seals and/orglands with minimal clearance, and the sealing action of such seals orglands also improves when the inner race 16 and/or the third wall 46 isacted upon by centrifugal force. Thus, each projections 53a penetratesinto the adjacent surface to form therein a temporary or permanentgroove or recess and to thus enhance the sealing action. The sealingaction of the projection or projections 53a can be enhanced stillfurther if the third wall 46 consists of a deformable plastic materialor if the radially outer side of the third wall 46 is coated with alayer of deformable plastic material. The same holds true if theprojection or projections 53a or analogous projections are provided atthe outer side of the third wall 46 to penetrate into the material ofthe inner race 16 or into a deformable liner which coats the internalsurface of the race 16. The aforediscussed liner can consist of a heatinsulating plastic material, particularly if the third wall 46 is madeof metallic sheet material (FIG. 3).

The sealing ring 53 exhibits the advantage that it can perform theadditional function of preventing radial expansion of the outer race 17if the outer race constitutes a split ring which must be expanded inorder to permit insertion of rolling elements 6a' between the two races.Once the sealing ring 53 is applied subsequent to insertion of therolling elements 6a', the outer race is held in the radially contractedcondition to ensure that the radial width of the space between the races16, 17 is not increased in actual use of the bearing 6a.

The elastically deformable bead 62 of the sealing ring 53 contributes toreliable sealing action between the axially extending portion of thesealing ring and the outer race 17 as well as between the first wall 39of the enclosure 38 and the sealing ring. The sealing action isparticularly satisfactory if the bead 62 is installed in deformedcondition such that it is stressed in the axial and/or radial directionof the race 17.

A bearing which does not employ a cage (6b) and wherein the rollingelements constitute spheres is preferred in many instances because it iscapable of standing elevated stresses as a result of an increase of thenumber of rolling elements.

As mentioned above, the rolling elements 6a' can be readily introducedinto the tracks of the races 16, 17 if the outer race is split so thatit is capable of undergoing radial expansion. The radial expandibilityno longer exists when the application of the sealing ring 53 iscompleted because this ring holds the outer race against radialexpansion.

The races 16, 17 and the rolling elements 6a' between them constitute apreassembled unit or module as soon as the application of the enclosure38 and sealing ring 53 is completed. Such prefabricated module can bemanipulated in a time saving manner.

The frustoconical portions 42, 44 of the second wall 40 of the enclosure38 constitute an optional feature of the improved module. Suchconfiguration of portions 42, 44 of the second wall 40 promotes the flowof lubricant toward the rolling elements 6a'. In addition, the conicalexternal surfaces of portions 42, 44 can serve as ramps for moreconvenient installation of the module including the races 16, 17,rolling elements 6a', enclosure 38 and sealing ring 53, for example,during introduction of the module into

the central opening 3a of the secondary flywheel 3.

FIG. 3 shows a modified friction reducing unit 106 having anantifriction bearing 106a. All such parts of the structure of FIG. 3which are identical with or clearly analogous to the corresponding partsof the structure shown in FIG. 2 are denoted by similar referencecharacters plus 100. An important difference between the embodiments ofFIGS. 2 and 3 is that the enclosure which is shown in FIG. 3 is made ofa metallic sheet material and includes two sections 138, 170. Thesesections jointly form a cylindrical first wall which surrounds theperipheral surface of the outer race 117 and is surrounded, in turn, bythe internal surface of the secondary flywheel 103. The section 170 ofthe enclosure which is shown in FIG. 3 performs the function of thesealing ring 53 of the embodiment of FIG. 2 in that it establishes aseal at the left-hand axial end of the space including that between theraces 116 and 117 and confining the spherical rolling elements 106a'.

If it is desired to enhance the heat insulating properties of theenclosure for the bearing 106a of FIG. 3, the sections 138, 170 of theenclosure are made of a suitable plastic material, e.g., the material ofwhich the enclosure 38 of FIG. 2 is made. Adequate thermal insulation ofthe bearing 6a or 106a (and especially of the lubricant for the rollingelements 6a' or 106a') is desirable because the secondary flywheel 3 or103 is likely to be heated to an elevated temperature during engagementor disengagement of the friction clutch 4, i.e., when the clutch plate 5slips relative to the pressure plate 26 and the secondary flywheel 3 or103. Excessive heating of the bearing 6a or 106a is undesirable on theadditional ground that this would result in uncontrollable thermalexpansion of the inner and/or outer race so that the primary and/or thesecondary flywheel would run out of true. Still further, undue expansionof the races of the bearing 6a or 106a could interfere with the freedomof rotation of the two flywheels relative to each other.

The section 138 of the enclosure which is shown in FIG. 3 is similar tothe enclosure 38 for the flywheels 16, 17 of FIG. 2. The main differenceis that the axially extending first wall of the section 138 overliesonly approximately one-half of the peripheral surface of the outer race117. The section 170 has an L-shaped cross-sectional outline with anaxially extending cylindrical leg 170a which overlies the other half ofthe peripheral surface of the outer race 117 and a radially extendingring-shaped or washer-like leg 117b which overlies the left-hand endfaces of the races 116, 117. The radially inner portion of the leg 117bmay but need not actually contact the adjacent end face 116b of theinner race 116; at any rate, the leg 117b and the inner race 116preferably establish a seal against the escape of any, or against theescape of excessive quantities of, lubricant from the space between theraces 116 and 117.

Each of the sections 138, 170 can be a press fit on the outer race 117.In addition to or in lieu of such mounting, the section 138 and/or 170can be bonded (e.g., with a suitable adhesive) to the outer race 117.The shaping of sections 138, 170 can be completed before the twosections are slipped onto the respective axial ends of the outer race117.

The radially inner portion of the radially extending leg 170b of thesection 170 is received in a shallow cutout

or depression 115b which is provided in the hollow protuberance 115 ofthe primary flywheel adjacent the cylindrical end portion 115a. Theclearance between the bottom wall of the recess 115b and the adjacentend face 116b of the inner race 116 is sufficient to snugly receive theradially inner portion of the leg 170b. The inner race 116 is or can bea press fit on the cylindrical portion 115a.

The structure of FIG. 3 further comprises a modified sealing ring 153which is installed in the left-hand end portion of the annular spacebetween the races 116, 117. This sealing ring is preferably reinforcedor armored, e.g., in the same way as described with reference to thesealing ring 53 of FIG. 2. Thus, the ring 153 can also include areinforcing section of a metallic material and a second section ofelastomeric plastic material. As can be seen in FIG. 3, the sealing ring153 is installed in the space between the races 116, 117 adjacent themedian or intermediate portion of the radially extending leg 170b of thesection 170 of the enclosure or jacket for the two races. The leg 170bcooperates with the ring 153 to establish a dual sealing action at theleft-hand axial end of the space between the flywheels 116 and 117.

The bead 164 of the elastic section of the sealing ring 153 is receivedin an undercut groove 163 which is provided in the internal surface ofthe outer race 117. The bead 164 is preferably installed in axiallyand/or radially stressed condition and is closely or immediatelyadjacent the radially extending leg 170b of the section 170.

The encapsulation of lubricant in the antifriction bearing 206a of thefriction reducing unit 206 of FIG. 4 is analogous to or identical withthe encapsulation (in 38, 53) of the bearing 6a of FIG. 2. The enclosure238 is confined in the central opening of a secondary flywheel 203forming part of a composite flywheel 201 which further includes aprimary flywheel 202.

The inner race 216 of the bearing 206a has an L-shaped cross-sectionaloutline and is made of a metallic sheet material. This inner racecomprises an axially extending cylindrical portion or leg 216a whichdefines a track for the rolling elements 206a', and a radially inwardlyextending washer-like or disc-shaped portion or leg 216b engaged by theheads of fasteners 208 which serve to secure the primary flywheel 202 tothe crankshaft or to another suitable rotary output element of anengine. The axially extending leg 216a is provided with two or moretracks if the bearing 206a comprise two or more rows or annuli ofrolling elements 206a'.

The leg 216b of the inner race 216 has openings 271 in a distribution(as seen in the circumferential direction of the flywheel 202)corresponding to that of openings 207 for the shanks of fasteners 208.The openings 207 are provided in the flywheel 202 radially inwardly ofthe axially extending cylindrical leg 216a of the inner race 216. Thisinner race is centered by the radially extending portion 214 of theprimary flywheel 202, namely by a set of centering projections 272 whichare adjacent the internal surface of the radially extending leg 216b ofthe inner race. Proper centering of the inner race 216 on the primaryflywheel 202 results in proper centering of the outer race 217 andsecondary flywheel 203.

When the composite flywheel 201 is properly mounted on the outputelement of the engine, the radially inner part of the radially extendingportion 214 of the flywheel 202 is clamped between the flange (notshown) at the adjacent end of the output element and the heads of thefasteners 208 which urge the radially extending leg 216b of the innerrace 216 toward the adjacent side of the portion 214. In other words,the fasteners 208 can be said to secure the inner race 216 to the outputelement of the engine.

The outer race 217 can also be made of metallic sheet material.

The damping action between the flywheels 202 and 203 can be enhanced ifthe apparatus including the structure of FIG. 4 comprises a damper(corresponding to the damper 9 of FIG. 1) which acts circumferentiallyof the composite flywheel 201, and with a damper 273 which generatesfriction and can be responsive to load or can generate a delayedfrictional damping action. The illustrated second damper 273 isinstalled directly between the flywheels 202, 203 and is adjacent theinner side of the radially extending portion 214 of the primary flywheel202 at the radial level of the antifriction bearing 206a, i.e., close tothe output element of the engine. As can be seen in FIG. 4, the damper273 comprises a disc 274 which is made of metallic sheet material andincludes a substantially radially extending radially outer portion 275in engagement with a friction ring 276 which is biased by a diaphragmspring 277. A pressure transmitting washer 278 is disposed between thefriction ring 276 and the diaphragm spring 277. The radially extendingradially inner portion 279 of the disc 274 has cutouts for the shanks ofthe fasteners 208 and is clamped between the radially inner part ofportion 214 of the flywheel 202 and the radially extending leg 216b ofthe inner race 216.

The radially outer portion of the diaphragm spring 277 reacts againstthe portion 214 of the flywheel 202 and its radially inner portion bearsupon the washer 278. The washer 278 and/or the diaphragm spring 277 isprovided with projections 280, 281 in the form of lugs which extend inthe radial direction from the radially innermost part of the spring 277and/or washer 278 and are received in sockets (recesses or cutouts) 282of the disc 274 to prevent rotation of the washer 278 and/or spring 277relative to the disc 274. The friction ring 276, the washer 278 and thediaphragm spring 277 surround an axially extending portion 283 of thedisc 274; the axially extending portion 283 connects the radiallyextending portions 275 and 279 of the disc 274.

The friction ring 276 extends radially outwardly beyond the radiallyoutermost portion of the disc 274 and is provided with abutments orprojections 284 which, in the embodiment of FIG. 4, are obtained byproviding the friction ring 276 with radially extending cutouts whichalternate with the projections 284. The projections 284 cooperate withcomplementary projections or abutments 285 which are provided on thesecondary flywheel 203. In the embodiment of FIG. 4, the projections 285of the secondary flywheel 203 are pins or studs which are anchored inand extend axially of the secondary flywheel so that each thereof canenter a recess between two neighboring projections 284 of the frictionring 276. The arrangement is preferably such that the width of therecesses or cutouts between the projections 284 of the friction ring 276exceeds the diameters of the pins or studs 285 to thus ensure that theparts 203, 276 have limited freedom of angular movement relative to eachother. This results in the establishment of a delayed frictional dampingaction whenever the direction of rotation of the flywheel 203 relativeto the flywheel 202 (or vice versa) is reversed. The extent of suchdelay prior to development of frictional damping action can be selectedby the manufacturer as a result of appropriate dimensioning of the pinsor studs 285 and/or as a result of appropriate selection of the width(in the circumferential direction of the flywheel 203) of the recessesor cutouts between neighboring projections 284 of the friction ring 276.

It is possible to modify the structure of FIG. 4 in such a way that thepins or studs 285 are snugly received in the recesses between theneighboring projections 284 so that a frictional damping action isestablished as soon as one of the flywheels 202, 203 begins to turnrelative to the other in either direction. The frictional damping device273 is then active to assist the primary damper (corresponding to thedamper 9 of FIG. 1) during each and every stage of relative angularmovement between the flywheels 202 and 203.

The improved bearing and the apparatus utilizing such bearing aresusceptible of numerous additional modifications. For example, thefeatures of the structure which is shown in FIGS. 1 and 2 can becombined with those of the structure shown in FIG. 3 and/or 4, and thefeatures of the structure which is shown in FIG. 3 can be combined withthose which are shown in FIG. 4. Furthermore, the invention is embodiedin the antifriction bearing, in a combination of such bearing with anenclosure and/or sealing ring, as well as in a combination of thebearing with other component parts of the improved torque dampingapparatus. As presently advised, particularly the structure which isshown in FIG. 4 (and employs a bearing with an enclosure and a sealingring corresponding to or identical with those shown in FIG. 2) embodiesa number of features which are novel per se as well as in variouscombinations with one another.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic and specific aspects of our contributionto the art and, therefore, such adaptations should and are intended tobe comprehended within the meaning and range of equivalence of theappended claims.

We claim:
 1. A bearing for use between first and second rotarycomponents, comprising:an outer race; an inner race which is coaxialwith, at least partly surrounded by and disposed radially inwardly ofsaid outer race, and an enclosure including a first wall between saidouter race and one of said components, a second wall extending from saidfirst wall inwardly along an axial end of said outer race to an axialend of said inner race and a third wall which is surrounded by saidinner race, said second wall having a lubricant-confining pocketextending substantially axially of said races and away from said axialends.
 2. The bearing of claim 1, wherein said components constituteprimary and secondary flywheels of a composite flywheel and said onecomponent is said secondary flywheel.
 3. The bearing of claim 1, whereinsaid enclosure contains a heat insulating material.
 4. The bearing ofclaim 1, wherein said inner race has an internal surface provided with arecess for said third wall.
 5. The bearing of claim 1, wherein saidthird wall and said inner race defines at least one gland.
 6. Thebearing of claim 5, wherein said at least one gland has at least oneclearance.
 7. The bearing of claim 1, wherein said third wall and saidinner race define a friction bearing.
 8. The bearing of claim 1, whereinsaid third wall and said inner race have confronting surfaces and atleast one of said confronting surfaces has at least one annularprojection extending toward the other of said confronting surfaces. 9.The bearing of claim 1, wherein said enclosure contains a plasticmaterial.
 10. The bearing of claim 9, wherein said plastic material is aheat insulating material.
 11. The bearing of claim 1, wherein saidenclosure contains a metallic sheet material.
 12. The bearing of claim1, further comprising a sealing ring between said races, said raceshaving second axial ends remote from said second wall and said sealingring being disposed at said second axial ends.
 13. The bearing of claim12, wherein said outer race has an internal surface and an axialextension adjacent said internal surface at said second axial endthereof, said sealing ring having a portion which surrounds saidextension.
 14. The bearing of claim 12, wherein said outer race has anexternal surface provided with an annular recess at said second axialend thereof, said sealing ring having a substantially axially extendingradially outer portion in said recess.
 15. The bearing of claim 12,wherein said sealing ring includes a radially outer portion between saidouter race and said first wall.
 16. The bearing of claim 15, whereinsaid radially outer portion of said sealing ring comprises an elasticannular bead.
 17. The bearing of claim 16, wherein said bead is stressedin at least one of two directions including axially and radially of saidraces.
 18. The bearing of claim 17, wherein said outer race and saidfirst wall have confronting surfaces flanking said bead, at least one ofsaid surfaces having an annular groove and said bead being received insaid groove.
 19. The bearing of claim 1, wherein said inner race has asubstantially L-shaped cross-sectional outline and includes asubstantially axially extending first leg and a second leg, and furthercomprising means for coupling said second leg to said last named onecomponent.
 20. The bearing of claim 19, further comprising at least onerow of rolling elements between said races, said first leg of said innerrace having a track for said at least one row of rolling elements. 21.The bearing of claim 19, wherein said components include a primary and asecondary flywheel and said coupling means is provided between saidsecond leg and said primary flywheel.
 22. The bearing of claim 19,wherein said second leg extends substantially radially inwardly of saidfirst leg.
 23. The bearing of claim 19, wherein at least one of saidlegs consists of metallic sheet material.
 24. The bearing of claim 1,further comprising at least one row of spherical rolling elementsconfined between said races.
 25. The bearing of claim 24, wherein saidrolling elements are confined exclusively by said races.
 26. The bearingof claim 1, further comprising at least one row of rolling elementsbetween said races, at least one of said races being split to facilitateintroduction of said rolling elements between said races.
 27. Thebearing of claim 1, further comprising at least one row of rollingelements between said races, said outer race being expandible andcontractible to permit introduction of said rolling elements betweensaid races and further comprising means for maintaining said outer racein contracted condition upon introduction of rolling elements betweensaid races.
 28. The bearing of claim 27, wherein said means formaintaining comprises a sealing ring.
 29. The bearing of claim 1,wherein said enclosure and at least one of said races constitute aprefabricated module.
 30. A bearing for use between first and secondrotary components, comprising:an outer race; an inner race which iscoaxial with, at least partly surrounded by and disposed radiallyinwardly of said outer race, and an enclosure including a first wallbetween said outer race and one of said components, a second wallextending from said first wall inwardly along an axial end of said outerrace to an axial end of said inner race, said second wall comprises afirst portion between said first wall and said pocket and a secondportion, said pocket being disposed between said first and secondportions and at least one of said first and second portions making anoblique angle with the common axis of said races, said second wallhaving a lubricant-confining pocket extending substantially axially ofsaid races and away from said axial ends.
 31. The bearing of claim 30,wherein said at least one portion of said second wall is a hollowconical frustum.
 32. A bearing comprising an outer race having aperipheral surface, a first axial end and a second axial end; an innerrace coaxial with and at least partially surrounded by said outer raceand having first and second axial ends at the first and second axialends, respectively, of said outer race, and an internal surface; and anenclosure having a first wall adjacent the peripheral surface of saidouter race, a second wall at the first axial ends of said races, and athird wall surrounded by a portion of said internal surface.